This resubmission of application 1 R01 AG051723-01 seeks 5 years of funding to conduct a randomized con- trolled trial (RCT) to test the efficacy of a multi-component intervention called AgingPLUS. AgingPLUS targets neg- ative views on aging (NVOA), low control beliefs, and deficient goal-planning as a cluster of risk factors for un- healthy aging. Specifically, we will examine whether making adults' NVOA more positive and strengthening their personal control beliefs and goal planning will result in increases in physical activity (PA). PA is chosen as the outcome behavior of interest because it is the best non-pharmacological, non-invasive, and most cost-ef- fective method of health promotion. The proposed study addresses several issues of critical importance to indi- viduals and society at large. First, the project extends a large body of evidence showing that NVOA, low control beliefs, and poor goal-planning keep adults' from engaging in health-promoting behaviors, including engage- ment in PA. Second, the project also responds to calls for intervention programs that address attitudinal and motivational factors that undermine adults' ability to age in healthier ways. Finally, the project addresses critical issues with regard to the long-term maintenance of positive behavior change. The proposed project has three specific aims: 1. To conduct a randomized trial to examine the efficacy of the AgingPLUS program. Using a randomized single-masked pretest-posttest design with a social contact control group, we will examine if adults' NVOA, personal control beliefs, and goal planning can be improved over the course of a 4-week intervention pro- gram. 2. To test a conceptual model of the mechanisms underlying the intervention effects. Because partici- pants in the AgingPLUS group will practice a self-defined PA goal after they have completed the intervention, we will use accelerometry and daily activity logs to assess their PA. Using a multiple mediator model, we will examine if improved NVOA, control beliefs, and goal planning are the putative mechanisms that pro- duced the change in PA. We hypothesize that improvements in NVOA, control beliefs, and goal planning will be significant mediators of the association between the intervention and PA at the Week 8 posttest. 3. To conduct a 6-months follow-up to examine the long-term effects of AgingPLUS. We will conduct a 6- month follow-up and use multilevel modeling to describe participants' change trajectories across all 4 times of assessment. In addition, we will examine if intermittent monitoring of participants' PA facilitates the maintenance of a physically active lifestyle. This aim examines the natural time course of the intervention effects to inform the next stage of development of the AgingPLUS program.